I believe you can do what you said. However, most people don't have the choice of installing off "non-optical" media and most don't get SSD drives (I've considered it, but not taken the plunge yet). Including the time spent selecting hardware -- reading reviews, comparing options, whatever -- is necessary for a valid cost comparison. The comparisons being made are cost vs. time and convenience. When I ordered my HP box earlier this year it took under 20 minutes.
Perhaps you and Bats should create a start-up together and reap the massive profits out of us lazy people.